Every service market is very particular, with respect to its organization, rule-making, impediments to trade, and the degree of liberalization achieved. The main objective of this article is to produce a sectoral study of maritime transport with a focus on preferential treatment. The General Agreement on Trade in Services (GATS) entered in force in 1995. Before GATS, a few Preferential Trade Agreements (PTAs) contained provisions that related to the liberalization of trade in services. Preferential treatment was granted through sector specific or horizontal agreements. Since 2000, we have witnessed a boom of PTAs in services (under article V of GATS). Maritime transport was no exception. Thus, in the sector, the pre-GATS preferential scheme comprised bilateral sector specific agreements called Bilateral Maritime Agreements (BMAs) and a multilateral treaty, the Convention on a Code of Conduct for Liner Conferences (UN Liner Code hereafter). In the post-GATS scheme, most preferences are granted through service-specific provisions contained in PTAs. The first objective of this paper is to show, a paradigm shift from a protectionist (and even exclusionary) to a more liberal treatment of preferences in bilateral maritime transport agreements from the early 1990s. This movement accelerated in 2000 with the development of PTAs in services. The second objective is to show that most of the old framework is outdated. The third objective is to show that the potential preferences granted within the new framework are substantial for some countries. Our analysis is based on agreements signed by 30 countries 2 between 1960 and 2009. The sample represents 224 BMAs and 49 PTAs.